POS1077 TIME TREND OF SEROPOSITIVITY IN JAPANESE PATIENTS WITH RHEUMATOID ARTHRITIS BETWEEN 2000 AND 2021: DATA FROM THE IORRA COHORT
Authors: T. Higuchi, E. Tanaka, E. Inoue, M. Abe, K. Saka, E. Sugano, N. Sugitani, M. Ochiai, R. Yamaguchi, K. Ikari, Y. Hisashi, M. Harigai
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> It has been reported that patients with rheumatoid arthritis (RA) differ in disease progression and responsiveness to treatment depending on their serological status. Examining time trends in serological status may lead to the recognition of changes in the phenotype of RA. Recent reports revealed that the incidence of rheumatoid factor (RF)-positive RA had been decreasing<sup>[1,2]</sup>. This needs to be further investigated in other registries and races; however, data from a large observational study of Japanese are lacking. <h3>Objectives</h3> We aimed to investigate the time trend of seropositivity in Japanese RA patients. <h3>Methods</h3> This is a retrospective study using data from the Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort. Among patients enrolled in the IORRA cohort between 2000 and 2021, patients with a disease duration of &lt;3 years at enrolment were included. Seropositive status was defined as positive for rheumatoid factor (RF) (cut-off: 15 IU/mL) and/or anti-cyclic citrullinated peptide (CCP) antibody (second generation; cut-off: 4.5 U/mL). Patients with one negative and one unmeasured or both unmeasured were excluded. The time period was divided into 2000–2010 and 2011–2021. The effect of the time period on seropositivity was analyzed using multivariable analysis after adjusting for age, sex, smoking, and body mass index (BMI) at enrollment. <h3>Results</h3> Of 6,514 patients enrolled, 5,289 (81.2%) patients were female, and the median age was 54.9 (interquartile range: 44.0–64.5). 5,142 (88.2%) were seropositive, and the proportion of serological status differed between 2000–2010 (n=4,261) and 2011–2021 (n=2,004) (Figure 1). The proportion of seropositive patients was 90.2% in 2000–2010 and 84.0% in 2011–2021. The positivity for RF and anti-CCP antibody was decreased over time: 74.9% and 78.1% in 2000–2010 and 70.0% and 74.3% in 2011–2021, respectively. The time period (2011–2021) was associated with seronegativity (adjusted odds ratio [OR]: 1.51, 95% confidence interval [CI]: 1.24–1.83). Additionally, the time period (2011–2021) was also associated with RF negativity (adjusted OR: 1.44, 95% CI: 1.23–1.68) and anti-CCP negativity (adjusted OR: 1.30, 95% CI: 1.10–1.52). <h3>Conclusion</h3> Analysis of the IORRA cohort data revealed a decrease in seropositivity in Japanese patients with RA. The phenotype of RA in the clinical setting may have been changing over time. <h3>References</h3> [1] Kaipiainen-Seppanen O, et al. J Rheumatol. 2006; 33(11):2132–8. [2] Myasoedova E, et al. Ann Rheum Dis. 2020; 79(4):440–4. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Tomoaki Higuchi: None declared, Eiichi Tanaka Speakers bureau: AbbVie Japan GK; Asahi Kasei Corp.; Astellas Pharma Inc.; Ayumi Pharmaceutical Co.; Chugai Pharmaceutical Co., Ltd.; Eisai Co., Ltd.; Eli Lilly Japan K.K.; GlaxoSmithKline K.K.; Kyowa Pharma Chemical Co., Ltd.; Janssen Pharmaceutical K.K.; Mochida Pharmaceutical Co., Ltd.; Pfizer Japan Inc.; Takeda Pharmaceutical Co., Ltd.; and Teijin Pharma Ltd., Eisuke Inoue Speakers bureau: Bristol Myers Squibb Co., Ltd.; Pfizer Japan Inc.; Nippontect systems Co., Ltd.; RCR Co., Ltd., Mai Abe: None declared, Kumiko Saka: None declared, Eri Sugano: None declared, Naohiro Sugitani: None declared, Moeko Ochiai: None declared, Rei Yamaguchi: None declared, Katsunori Ikari Speakers bureau: Asahi Kasei Corp.; Astellas Pharma Inc.; AbbVie Japan GK; Ayumi Pharmaceutical Co.; Bristol Myers Squibb Co., Ltd.; Chugai Pharmaceutical Co., Ltd.; Eisai Co., Ltd.; Eli Lilly Japan K.K.; Janssen Pharmaceutical K.K.; Kaken Pharmaceutical Co. Ltd.; Mitsubishi Tanabe Pharma Co.; Pfizer Japan Inc.; Takeda Pharmaceutical Co. Ltd.; Teijin Pharma Ltd.; and UCB Japan Co. Ltd., Yamanaka Hisashi Consultant of: CorEvitas LLC, Masayoshi Harigai Speakers bureau: AbbVie Japan GK; AstraZeneca K.K.; Ayumi Pharmaceutical Co.; Boehringer Ingelheim Japan Inc.; Bristol Myers Squibb Co., Ltd.; Chugai Pharmaceutical Co., Ltd.; Eisai Co., Ltd.; Eli Lilly Japan K.K.; GlaxoSmithKline K.K.; Gilead Sciences Inc.; Janssen Pharmaceutical K.K.; Kissei Pharmaceutical Co., Ltd.; Nippon Kayaku Co., Ltd.; Nippon Shinyaku Co., Ltd.; Novartis Japan; Pfizer Japan Inc.; CIMIC Holdings Co., Ltd.; Mitsubishi Tanabe Pharma Co.; Teijin Pharma Ltd.; and UCB Japan Co. Ltd., Consultant of: AbbVie; Boehringer-Ingelheim; Bristol Myers Squibb Co.; Kissei Pharmaceutical Co., Ltd.; and Teijin Pharma Ltd., Grant/research support from: Grant/research support from: AbbVie Japan GK; Asahi Kasei Corp.; Astellas Pharma Inc.; Ayumi Pharmaceutical Co.; Boehringer Ingelheim Japan, Inc.; Bristol Myers Squibb Co., Ltd., Chugai Pharmaceutical Co., Daiichi-Sankyo, Inc., Eisai Co., Ltd.; Kaken Pharmaceutical Co., Ltd.; Kissei Pharmaceutical Co., Ltd.; Mitsubishi Tanabe Pharma Co.; Nippon Kayaku Co., Ltd.; Sekisui Medical; Taisho Pharmaceutical Co., Ltd.; and Teijin Pharma Ltd.